Ultra wideband (UWB) technologies have been developed to exploit a new spectrum resource in substances and to realize ultra-high-speed communication, high precision geo-location, and other applications. The energy of UWB signal is extremely spread from near DC to a few GHz. This means that the interference between conventional narrowband systems and UWB systems is inevitable. However, the interference effects had not previously been studied from UWB wireless systems to conventional wireless systems sharing the frequency bands such as Satellite Digital Multimedia Broadcasting service. This paper experimentally evaluates the interference from two kinds of UWB sources, namely a Orthogonal Frequency Division Multiplex UWB source and an impulse radio UWB source, to a SDMB digital transmission system. The average Bit error rate degradation of each system are presented. From these experimental results, we show that in all practical case UWB system can coexist with SDMB terminal without causing any dangerous interference about maximum 2m distance.